Répondre :
Ex1:
[tex]A=\frac{(\frac{3}{16}-\frac{7}{12}+\frac{1}{4})\times(\frac{1}{24}-\frac{1}{24})}{(\frac{15}{8}-\frac{1}{4})} \\\\A=\frac{(\frac{3}{16}-\frac{7}{12}+\frac{1}{4})\times(\frac{0}{24})}{(\frac{15}{8}-\frac{1}{4})} \\\\A=\frac{(\frac{3}{16}-\frac{7}{12}+\frac{1}{4})\times0}{(\frac{15}{8}-\frac{1}{4})} \\\\A=\frac{0}{(\frac{15}{8}-\frac{1}{4})} \\\\A=0[/tex]
[tex]B=\frac{(1+\frac{1}{3}-\frac{1}{2})\times(-\frac{5}{6})}{(-\frac{3}{4})\times(1+\frac{1}{3}-\frac{1}{2})} \\\\(1+\frac{1}{3}-\frac{1}{2}) = (\frac{6}{6}+\frac{2}{6}-\frac{3}{6}) = \frac{6+2-3}{6} = \frac{5}{6} \\\\B=\frac{(\frac{5}{6})\times(-\frac{5}{6})}{(-\frac{3}{4})\times(\frac{5}{6})} \\\\B=\frac{-\frac{25}{36}}{-\frac{15}{34}} \\\\B = -\frac{25}{36}\times-\frac{15}{34} \\\\B = \frac{85}{54}[/tex]
Ex2:
[tex]x = \frac{-\frac{1}{4}+\frac{1}{6}}{2} \\\\x = -\frac{1}{8}+\frac{1}{12} \\\\x = -\frac{12}{96}+\frac{8}{96} \\\\x = -\frac{4}{96} \\\\x = -\frac{1}{24}[/tex]